function show (id) {
if (document.getElementById) 
document.getElementById(id).style.visibility = "visible";
else if (document.all) 
document.all[id].style.visibility ="visible";
else if (document.layers) 
document.layers[id].visibility = "show";
}

function hide (id) {
if (document.getElementById)
document.getElementById(id).style.visibility = "hidden";
else if (document.all)
document.all[id].style.visibility ="hidden";
else if (document.layers)
document.layers[id].visibility = "hide";
}



function showAndHide (which) {
	// deze functie zet eerst alle div's op hidden en dan een specifieke
	// div op visible.
	for (i = 1; i <= 7; i++) {
		if (i == which) show ('submenu' + i);
		else hide ('submenu' + i);
	}
}

function hideAll () {
	for (i = 1; i <= 7; i++) {
		hide ('submenu' + i);
	}
}